Neonatal azithromycin administration for prevention of infant mortality

Background. Biannual mass azithromycin administration reduces all-cause childhood mortality in some sub-Saharan African settings, with the largest effects in children aged 1-5 months. Azithromycin has not been distributed to children <1 month due to risk of infantile hypertrophic pyloric stenosis (IHPS). Methods. This 1:1 placebo-controlled trial, randomized neonates aged 8-27 days to a single oral dose of azithromycin (20 mg/kg) or equivalent volume of placebo in 5 regions of Burkina Faso during 2019 and 2020. The primary outcome was all-cause mortality at 6 months of age. Infants were evaluated at 21 days after treatment and at 3 and 6 months of age for vital status; family and provider surveillance for IHPS continued throughout. Results. Of 21,832 enrolled neonates, 10,898 were allocated to azithromycin and 10,934 to placebo. At 6 months of age, 92 infants had died, 42 (0.44%) in the azithromycin group and 50 (0.52%) in the placebo group (hazard ratio 0.85, 95% confidence interval 0.56 to 1.28, P=0.46). A single IHPS case was detected, which was in the azithromycin arm. Serious adverse events, including death and hospitalization within 28 days of treatment, occurred in 0.27% of infants in the azithromycin group and 0.14% in the placebo group, for an absolute risk difference 0.14 percentage points, 95% confidence interval 0.01 to 0.26. Conclusions. Overall mortality was lower than anticipated when the trial was designed, thus limiting its power. The available data do not support the routine use of azithromycin for prevention of mortality in neonates in sub-Saharan African settings similar to the one in which this trial was conducted. Trial registration. ClinicalTrials.gov NCT03682653


Author Contributions
The study was designed by CEO, AS, MB, EL, TD, TCP, and TML. Data collection and supervision was done by CEO, AS, MB, AZ, GC, TO, FK, EL, JB, FN, and TML. CEO, TCP, and BFA vouch for the data and the analysis. CEO wrote the first draft of the paper and all authors critically reviewed the paper. All authors decided to submit for publication.

Supplemental Methods
Adverse event screening protocol. Screening for infantile hypertrophic pyloric stenosis (IHPS) was conducted via active screening and caregiver report. During informed consent, all caregivers were informed of the risk of IHPS and signs to look for. They were asked to inform the study staff should their child experience projectile vomiting or vomiting after every feed. At the 21-day post-treatment visit, caregivers were asked a series of questions about vomiting. Caregivers of children with persistent projectile vomiting and/or who were vomiting after every feed were referred for an ultrasound. Note that children could be referred for an ultrasound outside of the active screening program, and children whose caregivers reported projectile vomiting that had resolved were not necessarily referred. Children who presented to a study facility for a non-planned study visit were screened for IHPS.
An ultrasound was considered positive for IHPS if the pyloric muscle thickness (diameter of a single muscular wall on a transverse image) was >4 mm, the length of the pylorus was >15 mm, or pylorus thickness and length were below these criteria, but no food could pass. The infant was transferred to a pediatric surgical facility in Ouagadougou or Bobo Dioulasso for further workup and pyloromyotomy if indicated. Prior to transfer, infants were assessed for electrolyte disturbance and dehydration and were stabilized. Any infant receiving surgery for IHPS was followed at 1 week and 4 weeks after the procedure to assess the child's vital status and monitor recovery. In addition to the active screening protocol, caregivers were educated about the risk of IHPS during the informed consent procedure and were asked to contact study staff immediately in the event their child developed projectile vomiting or if they were otherwise concerned about IHPS or another adverse event.
All serious adverse events, including IHPS, as well as hospitalization and deaths within 28 days of treatment, were reported to the study's medical monitors within 24 hours of the study team becoming aware of them. If the medical monitors deemed the serious adverse event to be possibly related to study treatment, they were reported to the Data and Safety Monitoring Committee (DSMC) within 24 hours.
In addition to IHPS and other serious adverse events, caregivers were asked at the 21-day visit about other non-serious adverse events that their child had experienced since treatment. These including diarrhea, fever, abdominal pain, rash, and constipation. Non-serious adverse events were reported overall and by specific category. Non-serious adverse event data were collected through August 2020 (for approximately two-thirds of participants).

Interim analysis methods.
A single interim analysis for efficacy at an alpha of 0.001 was prespecified when the first one-third of the planned study population (N=7,238) reached their primary endpoint or at the end of the first full year of enrollment, whichever occurred first. The one-third enrollment goal was achieved in February 2020 and the interim analysis was completed in October 2020. The interim analysis additionally included an analysis of futility using simulation, with a stipulation to discontinue the trial at the discretion of the DSMC if conditional power dropped below 10%. Interim analyses for safety included tabulation of IHPS cases by study group, and the pre-specified interim analysis plan stipulated that while statistical tests would be reported, the decision to discontinue for safety would not be made solely on the basis of statistical considerations. Finally, all other adverse events were summarized overall and by study group, including the risk difference for adverse events by arm and corresponding 95% confidence intervals.
Protocol changes. The trial's original protocol stipulated 3 weekly follow-up visits for adverse events at days 7, 14, and 21 after treatment. Due to the low incidence rate of IHPS and reports of projectile vomiting, the adverse event screening was changed in July 2020 from 3 weekly visits to a single adverse event screening at 21 days after treatment. At the time the change was implemented, 14,591 participants had been enrolled. This change was reviewed and approved by the DSMC and in the Institutional Review Boards in the United States and Burkina Faso. During implementation of the change, an error was introduced in the study's mobile data application that affected branching logic for adverse event questions was introduced, which meant that children who had a 21-day visit after this change was made were not actively screened for adverse events. Data were collected for these children regarding clinic visits and hospitalizations, and serious adverse events were collected as usual and reported to the DSMC. After the error was discovered, the study team traced children enrolled after the change for whom the study had no collected vital status to determine whether any of the children could have had IHPS. No suspected cases of IHPS were detected through this follow-up. For analytic purposes, an infant was considered to have experienced an adverse event if they had experienced one on any of the 3 follow-up visits prior to the change in protocol. No other protocol changes were implemented during the course of the trial. Figure S1. Map of study enrollment sites Table S1. Baseline characteristics by retained or not retained in the primary analysis (6-month mortality among children measured in the pre-specified window)  Table S3. Sensitivity analysis for the primary outcome (mortality at 6 months of age) including all children with vital status information regardless of whether the child was measured in the prespecified measurement window for the primary analysis. The hazards ratio (HR) was estimated with a binomial regression model with a complementary log-log link with treatment group as the sole predictor. The P-value was estimated used a two-sided permutation test of the log hazard ratio with 10,000 iterations.

Azithromycin
Placebo 6-month mortality N n % N n % HR (95% CI) Pvalue* All children regardless of window 10453 42 0.4% 10489 50 0.5% 0.84 (0.56 to 1.27) 0.42   Infant mortality is higher in rural compared to urban settings, where socioeconomic status is generally lower and there is reduced access to healthcare. Infant mortality is higher in undernourished babies and those born low birthweight. Overall representativeness of this trial Participants in this trial were 50% male and 50% female, as expected. The infant's biological sex was ascertained by asking the caregiver if the infant was male or female. Infants were most commonly enrolled during the 2 nd week of age, and median age at enrollment was 11 days, so the age distribution at enrollment skewed younger than the general population. All participants were Black. Participants were more often urban compared to rural-dwelling due to the need to enroll participants near facilities with pediatric surgical capacity. Participants were less often low birthweight and underweight compared with the general population, and thus likely to have lower mortality rates than the general population of Burkina Faso.
Data on trends in infant and childhood mortality in Burkina Faso was based on UNICEF data from 2019.